Pharmacologic disposition studies are in progress for several new antitumor agents. These compounds are either in early stages of clinical evaluation or are under consideration for clinical trial. By selecting compounds early in their development, information as to their distribution, metabolism, absorption, etc. can be made available to clinicians along with recommendations to aid in the design of the clinical trial. Such information is essential for a successful clinical evaluation of the agent. Studies in laboratory animals were continued (see previous report) for three agents (coralyne sulfoacetate (NSC-154980), an acridine derivative (NSC-141549), inosine dialdehyde (NSC-118994)). Studies were initiated for three additional agents in laboratory animals (3-deazauridine (NSC-126849), spirohydantoin mustard (NSC-172112) and chlorozotocin (NSC-178248)). In addition, the pharmacokinetics of gallium were continued in humans in conjunction with phase I clinical trial.